CO-sensors: Cheap vs expensive, what's the difference?

I'm working on a DIY CO-sensor and coming across all different kinds of sensors (from MQ-7 to Figaro TGS5141, ME2-CO). I've read some posts here regarding the difference and it's mainly based on calibration. Other than that, is there a difference in accuracy, lifetime, temperature/humidity ranges etc?

Analog is more sensitive and less susceptible to respond to other things (like volatile organic compounds). The downside is that it has will only work for a few years, since it has some material inside that slowly reacts.